Sid mistakes it for politeness at first.
Not that Sid knows what politeness looks like on Sullivan, not exactly. The new Inspector is never polite to him - in fact, he's usually downright hostile - so perhaps it isn't politeness at all, perhaps it's just awkwardness.
Whatever it is, Sid has noticed that Sullivan behaves differently around women.
Sid watches him. He watches the uncomfortable shift of Sullivan's body whenever Lady F brushes past him, the way he tips his hat, gaze averted, every time a woman talks to him, as though prolonged eye contact might be considered improper.
Sid can't understand it himself; that primness, that propriety. It irritates him.
Inspector Sullivan's arrival is the talk of the village, and with looks like that, Sullivan could have his pick. God knows, half the female population of Kembleford have been speculating about Sullivan's marital status. If Sid were in his position, he'd capitalise on that new-found attention, but instead Sullivan wastes it, shying away as if he's taken a vow of celibacy. Which is all well and good for the likes of Father Brown and Bishop Talbot, but Sullivan isn't a member of the clergy. From what Sid has heard, Sullivan isn't even religious.
It doesn't appear to be abstinence either. On the few occasions where Sullivan has joined the rest of them at functions, Sid has seen him drink and smoke. And if he doesn't subscribe to the belief that sex outside of marriage is wrong, then really, what's stopping him?
Some men lack confidence, Sid supposes. Though if Sullivan is one of them, he certainly doesn't let it impact on any other aspect of his life.
At work, Sullivan is every bit the arrogant Inspector. He's stubborn and rude and bloody-minded, and he seems to take an almost sadistic pleasure in chasing Sid and the Father away from his crime scenes, insisting that he knows best. If anything, Sid would describe him as arrogant. Self-assured.
So in the absence of a better explanation, Sid chalks up Sullivan's odd behaviour to a some sort of misguided attempt at etiquette.
It isn't long before something happens to blow that theory out of the water.
One hot afternoon in May, as Sid is working on the Rolls in front of the presbytery while he waits for Lady F to finish discussing plans for the summer fete. He is topping up the oil for the water pump, sweating in the heat of the midday sun, when he hears the low rumble of an engine approach. He looks up just in time to see the Wolseley draw up, grinding to a halt alongside him.
"All right, where is he?" Sullivan calls, climbing out and adjusting his cuffs. Poised and pristine, even in this weather.
Sid straightens himself up from where he has been hunched over the bonnet. "Good afternoon to you too, Inspector."
"Don't start. Just tell me where he is."
"Where who is?"
"You know who."
"Well, as you're here, I could probably hazard a guess, yeah."
"Is he inside?"
"I dunno." Sid grins. It's too easy, winding Sullivan up. "I'm not his keeper."
Sullivan scowls. "No, I didn't think you'd know, somehow."
"Then why did you ask?"
"Because Father Brown has been meddling in one of my cases again."
"Oh," says Sid. "I s'pose you'd better go and look for him yourself then, hadn't you?"
"Yes, thank you, Mr. Carter. Helpful as ever."
Sid laughs, cleaning his hands off on a piece of old cloth, before swiping his forearm across his brow. Even with his uniform jacket strewn across the front seat, his sleeves rolled up, and the top three buttons of his shirt unfastened, the heat is getting to him. How Sullivan always manages to look so unaffected and well put-together is a mystery. It's like the man has evolved beyond the need to sweat.
Sid slings the rag into the footwell and closes the driver's side door. When he looks up again, Sullivan is still standing there, eyes on him, frowning at his unbuttoned shirt, as though Sid should somehow be immune to the heat too. Under Sullivan's scrutiny, Sid feels his pulse quicken and his skin grow impossibly hotter.
"What?" he asks, annoyed.
Sullivan doesn't answer, only jumps slightly, looking up at Sid's face again.
"We can't all hide away in our nice, cool offices," Sid continues. "Some of us actually have to work for a living."
Sid is expecting a sarcastic remark about some of the less honest means by which he earns his money, but Sullivan doesn't rise to the bait. There is a momentary flash of something unidentifiable in Sullivan's eyes before he looks away completely, swallowing hard.
"Just tidy yourself up, for pity's sake, Carter," he spits, turning towards the presbytery. "You look a mess."
For a moment, Sid is so taken aback at Sullivan's outburst that he doesn't register the twitch of Sullivan's jaw, the way his voice quavers. He watches Sullivan walk away, unexpectedly stung by his words.
This wasn't their usual banter - teasing, with a bit of an edge. This was cruel. It takes Sid a few seconds to realise that Sullivan was lashing out. Not angry, but panicked. Defensive. As though he had been caught in the act, except the only thing Sid had caught him doing was-
Well, that certainly puts a different spin on things.
The intensity of Sullivan's gaze, the way his eyes had roved over Sid's exposed chest... What if Sullivan wasn't looking at him with disapproval at all?
Sid's stomach flips.
That would explain Sullivan's alarm. It would also go a long way to explaining why Sid has never seen him looking at women...
Sid starts down the path after him. He doesn't know what he plans to say, whether he wants to say anything at all, but by the time he reaches the garden, it's too late. Mrs. M has already opened the door, and Sullivan steps inside, disappearing from view.